


Love is Just an Experiment

by multifandom_fanatic



Category: Sherlock (BBC), Sherlock (TV)
Genre: Alternate Universe, Angst, Angst with a Happy Ending, Christmas, Christmas Fluff, Christmas Party, Curious Sherlock, Developing Relationship, Experiment, First Christmas, Fluff, Fluff and Angst, Jealous John, Johnlock - Freeform, Love Confessions, M/M, Romance, Sentimental Sherlock, Sherlock Holmes and Experiments, how their first christmas should have happened, slight AU
Language: English
Status: Completed
Published: 2015-01-24
Updated: 2015-01-24
Packaged: 2018-03-08 19:36:13
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,624
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/3220883
Author URL: https://archiveofourown.org/users/multifandom_fanatic/pseuds/multifandom_fanatic
Summary: <blockquote class="userstuff">
              <p>Johnlock. Slight AU to their first Christmas together. Sherlock has a hypothesis about John's feelings towards him. He decides to create an experiment to get John to admit his feelings before Christmas.</p>
            </blockquote>





	Love is Just an Experiment

**Author's Note:**

> Hi readers!
> 
> Finally, I decided to write my own Johnlock story. This is for a contest on tumblr that I saw. It's a holiday themed Johnlock story since it's that time of year again. I hope you all like it as much as I do. I had an absolute blast working with these characters and perfecting how to capture each one's personality. 
> 
> Sophie Horan Tomlinson Irwin Hood Malfoy Grimes Holmes xxxxxx

Sherlock strategically waited behind the door, as Molly entered the room. She jumped when she saw his reflection in the stainless steel door. "What are you doing here?" Molly asked.

"Looking for you. I need your help with something. An experiment, if you will," Sherlock replied, shrugging his shoulders nonchalantly.

"Why not ask, John? I'm sure he'd be perfectly happy to help you," Molly said, glancing at Sherlock wearily.

"Because it involves John," Sherlock said, rolling his eyes as if the answer had been obvious.

"What about him, exactly?" Molly asked curiously.

"I have a hypothesis about John, and I want to test it. To prove my hypothesis is correct though, I need you to act as my girlfriend."

"You want me to be your girlfriend?" Molly asked, a blush crossing her cheeks.

"Not my real girlfriend. A fake one," Sherlock clarified. How this wasn't blatantly obvious was something Sherlock couldn't quite grasp. Was everything always so hard for other people to understand?

 "And how will that help prove anything?" Molly questioned.

"It just will. Meet me at Baker Street tomorrow evening," Sherlock said, turning around and leaving before Molly could reply.

"What if I'm going Christmas shopping tomorrow?" Molly asked, but it was too late. Sherlock was already gone.

 ~~~~~~~~~~~~~~~

"What do you mean you're busy? You don't have a single case," John stated, rather confused at Sherlock's statement.

"I'm busy tonight. If you are so desperate for milk, go to the store and buy some," Sherlock replied, not taking his eyes off of his laptop.

"Honestly, do you ever pull your weight around here?" John huffed as he grabbed a coat.

"It's cold outside, might need gloves," Sherlock said, his eyes never leaving the screen.

"Great deduction, Sherlock. Really. Spectacular observational skills you've got there," John snapped.

John glanced out the window. Sure enough, it was snowing. Sighing, he did as Sherlock had said, and grabbed a pair of gloves.

"Wallets' in the kitchen next to the glass of eyes," Sherlock said.

"Shut up," John said, even though his voice held a lot less malice than it had a few moments ago. "I swear to God, when I get back I'm finding you a case. I cannot take it when you go this long without one. You're awful when you're bored," John moaned, grabbing his wallet.

John wasn't surprised when Sherlock didn't reply. "Right then, I'm off," John stated. Sherlock didn't reply. "Living with you is a nightmare," John said on his way out, his tone bordering on affectionate.

Sherlock caught the tone and smirked to himself. He was only alone in the flat for a few minutes before Molly walked in.

"Ah, Molly, good. Phase one is already in action," Sherlock stated.

"Phase one? I'm sorry, what's phase one?" she asked. Either Sherlock didn't hear her, or decided he didn't feel like answering.

"This is excellent, most truly riveting," Sherlock muttered under his breath gleefully.

"What is? Sherlock, what's going on?" Molly asked, utterly lost.

"The experiment, of course," Sherlock replied.

"What experiment?" Molly asked again.

"John!" Sherlock said, as if his name made everything make sense.

"What about him?"

"I'm testing his jealousy and affection," Sherlock answered.

"Erm- why?" Molly questioned.

"Because it's part of my experiment. Oh yes, talking of that, you're coming with me on a case tomorrow. I need to determine what John's reaction will be when I replace him for the day," Sherlock said, putting his hands together under his chin.

At this point, Molly gave up. Getting a straight answer out of Sherlock was impossible to do, so she just decided to do whatever he wanted. "Okay, sure."

"You need to leave, before John gets back," Sherlock said, moving back towards the sofa. Molly took a few steps towards the door before Sherlock spoke up again.

"No! Wait. Come here," he said, motioning to the spot beside him on the sofa. Molly did as instructed, sitting down next to him.

"What am I doing here?" Molly asked anyway.

"Fake girlfriend, remember?" Sherlock replied.

"Oh, of course. If I'm here, it raises suspicion. John sees us together and..." Molly broke off.

"And John will be jealous that you were here with me," Sherlock finished her sentence. "You've got questions," Sherlock stated, seeing the look of confusion on Molly's face.

"Just one. Why would John be jealous of me?" Molly ventured to ask.

"Because, I'm quite sure John has feelings for me that go deeper than friendship," Sherlock finally said.

"That's what this experiment is about? You want to see if John's in love with you? Couldn't you just deduce that?" Molly rushed to ask.

"That's more than one question, but yes, that is what it's about. It's not something I can deduce, at least not with him," Sherlock said, frowning. It frustrated him. He could easily deduce everything. Except for this.

The door downstairs opened and Sherlock's eyes flashed towards their door. "John," Sherlock breathed quietly. He immediately shifted closer to Molly, placing his hand on her lower thigh. He winked at her just as the door opened.

"I got the milk and-" John broke off, startling at the scene in front of him. Sherlock quickly moved away, looking up at John carefully. "What-" John paused to clear his throat. "What is Molly doing here?" John asked, a tinge of anger evident in his voice.

"She just came to give me some information for a case," Sherlock replied. He kept a perfect mask up, not showing any emotions to John.

"Right," John said. He turned on his heel and marched into the kitchen. He put things away, slamming doors as he did.

"I should be going now," Molly said. The tension in the room was palpable.

She quickly left, leaving Sherlock and John alone. "What was she really doing here?" John asked, crossing his arms and frowning from his place in the kitchen.

"Information about a body in a morgue," Sherlock shrugged vaguely. Carefully, he scrutinized John. Every action and movement was stored into his mind palace. He had never seen John like this before. Then again, he had never flirted with a girl in front of him.

John's jaw was locked firmly. His arms were crossed over his chest, and his hands were in fists. His eyes were narrowed, and a faint red blush covered his cheeks. 'Ah, the wonderful signs of jealousy,' Sherlock thought proudly.

John scowled and turned away. "What are our plans for Christmas?" Sherlock randomly spoke up.

"What?" John asked, turning around from making himself a cuppa.

"What are we doing next week for Christmas, John? You know, that time of the year when everyone is sappy, and they give each other presents and babble on about the great things in life? All about sentiment," Sherlock explained, as if John were stupid.

"I know what Christmas is, Sherlock. I meant, why are you asking?"

This would be their first Christmas living together. 'Does that make it important?' John thought. As if reading John's mind, Sherlock said, "It's our first Christmas living here. Together. Just wondering what our plans were going to be," Sherlock said flippantly.

"We can invite everyone over on Christmas Eve, I guess. Have a mini party. Then just spend Christmas here, just the two of us," John said, gesturing to the flat.

'Just as I thought,' Sherlock speculated, grinning to himself. He gave John a nod, showing he agreed with what John had said. He shifted, lying down and splaying his head on the arm of the chair.

John moved back into the room. He placed a cup of tea down for Sherlock, before sitting in his own chair.

"You know, we really do need to find you a case. Even I'm tired of watching you sulk around waiting for something good to show up," John said.

"It'll happen soon. The game is on, John," Sherlock replied, closing his eyes. 'The game is on, indeed,' he thought, collecting the evidence of John's jealous behavior and storing it for later.

 ~~~~~~~~~~~~~~~

The vibration of Sherlock's phone caught John's attention. When Sherlock made no move to get up and get it, John took that as the answer that he was supposed to pick up the phone.

"Hello?" John said. "Yes, yes I'll tell him. Where are we going?" John asked. There was a pause before he spoke again. "Sure. When did it happen?" Another pause. "I'll let him know. Thanks, Lestrade," John said, putting the phone down.

"Case?" Sherlock asked.

"Yep, on the south side of London. Last night a man was killed out of the blue. They can't see any weapons on the scene," John said.

"Oh, wonderful. I do love a good mystery, too boring otherwise," Sherlock grinned, grabbing his coat. John moved to grab his coat, when Sherlock whirled around.

"No, you stay here," Sherlock, stated.

"Umm, what?" John asked, taken aback. Sherlock never made him stay behind. They always went to scenes together. That was how it worked.

"I'm taking Molly as my assistant today. Your services won't be needed on this case. Stay home. Spend time with Mrs. Hudson. I'm sure she would be delighted to have your company," Sherlock said, turning to face John.

"Molly? Why the hell would you take Molly? And why the hell would I stay behind?" John asked with a flash of rage.

"I feel like taking Molly. I'm getting to be too predictable. You don't have to be involved in all my cases, John," Sherlock said, pushing it off as if he didn't care for John's company.

John's nostrils flared with anger. "How dare you replace me with Molly!" John hissed. 'Anger. Jealousy. Betrayal,' Sherlock deduced.

"I'm not replacing you, John. Merely wanting someone else's opinion on the scene. We'll talk about this later. Lestrade will only start to call again if I don't get to the scene soon."

With that, Sherlock left a very confused John standing alone in the flat. Molly was waiting for Sherlock just outside. "How did it go?" she asked, waiting for Sherlock to call a cab.

"Brilliantly. He reacted exactly as I expected him to. He's angry that I would replace him, jealous that it's you I'm taking instead of him, and betrayed that I would just leave him behind and take someone else with me to a case," Sherlock cheerfully exclaimed.

"So, everything is going how you want it to?" Molly asked as the two of them entered a cab. Sherlock just smirked in response.

~~~~~~~~~~~~~~~~

The case had been rather easy. Slow poising from his wife. All the signs showed an unhappy marriage and from further inspection, his alcohol addiction made it easy for his wife to slip the poison into the drinks she made him at night. Of course, she had fled, but it wasn't hard to guess that she had gone to her sister for help. Sherlock had Lestrade go and make the arrest. Another easy case solved.

It had all happened without any problems. Sherlock didn't want to admit that something had felt off, though. Deep down, he knew it was John's absence that was making things seem different.

He missed John's presence. He had been slower on deducing what had happened, which, in turn, was because John hadn't been there to help. Experiments aside, he decided he wouldn't be leaving without John again in a hurry. Of course, he wasn't about to tell John any of this. It wouldn't be worth the ridicule if he did.

However, Sherlock happily returned to 221B, ready to continue his little "experiment." It had been going exactly how Sherlock had planned it. With such good progress, he knew he would get a confession from John soon.

"So, how was the case?" John asked as Sherlock walked in.

'Interesting. His words say intrigued, but his tone says he disinterested because he is angry with me for leaving,' Sherlock deduced.

"Boring. Classic. Wife poisoning husband because she wants to get rid of him," Sherlock said. He dramatically collapsed into his chair across from John.

"You're angry at me," Sherlock said, his eyes taking in John's posture.

"Great, another wonderful deduction there. Of course I am. You not only went to a case without me, but you took Molly instead. Of all people, you take Molly Hooper. I hope you two are happy together," John huffed, slamming his cup of tea down on the table.

'Jealous. Most definitely jealous,' Sherlock noted. John stood, knocking Sherlock's legs out of the way.

"Where are you going?" Sherlock asked, noticing John grab his coat.

"Out. I can't deal with you right now," John shouted.

"You wanted me to go on a case, so I did," Sherlock shot back.

"I meant on a case with me! Not some cheap replacement who clearly can't help you like I can!" John yelled before storming out.

"He's going to regret saying that later," Sherlock muttered to himself, as he picked up his laptop and typed out John's reactions. "Oh how right I was. I'm always right. John, you're so obvious with your feelings, you might as well knit it into one of those ridiculous jumpers and march around in it like a puppet on display," Sherlock said, grinning.

~~~~~~~~~~~~~~~

John came back later, carrying Chinese takeout for himself and Sherlock. When John offered Sherlock the food, Sherlock took it with a smile. "Thank you, John," Sherlock said.

"I'm sorry, what?" John asked, sitting down in his chair.

"I said, thank you, John. I do occasionally know how to show some manners," Sherlock replied. A red flush crossed John's face and he nodded.

Why was Sherlock being pleasant to him? They'd just had a row and now Sherlock was being nice? Yeah, John had brought him dinner, but still. He was just going to get himself food, but he cared too much for Sherlock.

He also knew from experience that if he didn't remind Sherlock to eat, he'd just get too absorbed into his cases and neglect to eat anything. It was John's way of taking care of Sherlock. He'd never tell the detective though. Sherlock was never one for sentiment, and John knew that.

"I'm sorry, for snapping earlier. I just- I'm not used to the idea of you going on cases without me, I guess," John mumbled.

"Understandable," Sherlock replied. The two fell into silence for a minute.

"Do you want me to decorate the place? For Christmas, I mean?" John asked nervously. Sherlock nodded in response.

"More your field than mine, anyway," Sherlock said.

John couldn't help but laugh. "I'd pay to see you in a jumper and Father Christmas hat," he chuckled.

"That, will never happen," Sherlock said with a look of disgust, before he too, burst out laughing. "I just realized how terrible of an idea a party is. I don't like people, or interacting with people for that manner," Sherlock sighed.

"We'll keep it small. Just invite Mrs. Hudson, Lestrade, Mycroft, and Molly, I guess," John listed.

"That works, I suppose. My brother though? Really? Can't we just send him a text?" Sherlock asked with a frown.

"Yes, your brother. He's your brother, Sherlock. And it's Christmas. The time of year when you put up with family and celebrate together," John said.

"Sentiment. I'll never understand it," Sherlock muttered. John laughed, which caused Sherlock to laugh. And that was how they spent the night, laughing at nothing. John let loose, but Sherlock never stopped watching John, deducing him, and even deducing himself.

~~~~~~~~~~~~~~~

A couple days later, Sherlock made his way down to Bart's to talk to Molly. He waited in the lab for her. It surprised Molly again to see him. "Why do you always do that?" she asked, placing a test tube into a rack on the counter.

"Boring if I just walk in like a normal person," Sherlock replied, glancing at Molly.

"What are you doing here, exactly?" she asked.

"Am I not aloud in the lab to do some work for a case?" Sherlock shot back.

"Yes, but you don't have any cases right now," Molly said with a grin.

"I need to keep my eye on you. You're getting too smart," Sherlock said with a wink. Molly laughed.

"I'm here because we are a few days away from the end of my experiment with John," Sherlock said casually. "As John so blatantly puts it, I am quite a drama queen. That means, I need to add a bit of drama if I want John to confess," Sherlock explained.

"Where are you going with this, Sherlock?" Molly asked carefully.

Sherlock flashed a smirk at Molly. "At the Christmas party tomorrow, you and I will kiss, in John's bedroom, on his bed," Sherlock stated casually.

"We're going to what?" Molly asked in total shock.

"John will be so angry that he will snap and confess immediately," Sherlock kept talking, ignoring Molly's question.

"Are you sure this is a good idea, Sherlock? I mean- it's not that I don't want to kiss you. I mean-uh- it's not like I want to kiss you either. I just- is this really the right way to do this?" Molly stuttered.

"I don't see why not," Sherlock said. Why would Molly question his experiment? Of course he knew that this was the right way to handle this. He knew everything. It was going to work perfectly. He had been right about everything else so far, so there was no reason it wouldn't work now.

 "Just follow my lead tomorrow," Sherlock stated before turning on his heel and leaving Molly utterly stunned and confused. Why had she agreed to help Sherlock in the first place?

 ~~~~~~~~~~~~~~~

The party was in full swing before Sherlock decided to finally venture out of his room and join the other people in his flat. He had spent time working out all the details of his experiment. Things had to go perfectly if he wanted John to confess. He had even snuck into John's room and added a few things, just for his own pleasure.

The only part left was letting Molly know when the time was right, and having John notice his disappearance, which wouldn't be too hard.

Sherlock stepped into the room, catching everyone's attention. "Merry Christmas, Sherlock," Mrs. Hudson called happily.

"Yeah, yeah, merry Christmas to you too, Mrs. Hudson," Sherlock replied, grabbing a drink and joining his brother in the kitchen.

"Why exactly are we having this little extravaganza? Bit corny for you, isn't it, Sherlock?" Mycroft asked.

"Yes, well it's what John wanted so..." Sherlock started to say.

"Ah, yes, what Dr. Watson wanted. And you are always so happy to do whatever it takes to please him, aren't you, brother dear? Got quite a soft spot for him, don't you?" Mycroft provoked.

"Listen, Mycroft, don't go getting all sentimental and cocky. It doesn't suit you either, brother dear," Sherlock snapped back.

"But you do care for him. I can see it in the way you act around him," Mycroft said, sounding pleased.

"Oh please, don't act like you just deduced that," Sherlock said, rolling his eyes.

"Maybe you should be a little less obvious then," Mycroft said, gloating. Sherlock sighed and shook his head. "Looks like you're the one who's slipping," Mycroft said, shrugging.

"I am not slipping," Sherlock said, offended at the accusation.

"If that's what you believe. I'll only say this once though, and only because it's Christmas. He's the right choice for you. He balances you well," Mycroft said. "Merry Christmas, little brother," he said, tilting his glass to Sherlock.

"Merry Christmas, Mycroft," Sherlock replied. He gave a curt nod to his brother before he made his escape from the kitchen to find Molly. It was time to receive his Christmas present.

He walked over to Molly and placed his hand on her shoulder. When she glanced up at him, he nodded his head towards the stairs. Catching the hint, Molly slipped out of the conversation with Lestrade and followed Sherlock up the stairs.

By the time she walked into John's room, Sherlock was sitting on John's bed. Molly took a deep breath and sat down next to Sherlock. "How long do we have before John starts to come looking?" Molly asked.

"Three, four minutes tops," Sherlock answered.

"What are you going to do when he walks in and see us, you know-?" Molly broke off.

"Well, you're going to leave, and I'm going to handle John," Sherlock said, his answer giving nothing away.

Molly glanced around the room, and saw a present on the table. She smiled softly. Obviously Sherlock cared a lot about John, or he wouldn't have gone to all of this effort with the so-called "experiment."

She had played her part, and unfortunately, it wasn't her business to snoop anymore after her services were not needed.

Soon enough, heavy footsteps were heard walking up the stairs. "Ready?" Sherlock asked. Molly nodded in agreement. Sherlock leant forward, running his fingers through her hair, and he moved to press their lips together. He rushed on quickly, deepening the kiss just as John opened the door.

"Sherlock you had better not be- WHAT THE HELL IS GOING ON?" John screamed, catching the scene unfolding in front of him.

The two broke apart quickly. Molly flushed bright red, and Sherlock scratched the back of his neck awkwardly. "John... well this is awkward," Sherlock said bashfully, looking down.

"Get. Out. Now." John seethed. Sherlock made to get up, along with Molly, when John shook his head. "Not you, just her. Get the hell out of my room," John hissed.

Molly bolted from the room and closed the door behind her, leaving John and Sherlock alone. \

"What in the hell do you think you are doing? Not only do you have the audacity to use my room, but also you choose to hook up with her of all people? I've had enough!" John yelled.

Sherlock's eyebrows knitted together in confusion. "Okay, I get that you're mad about us using your room, but why are you mad about it being Molly?" Sherlock asked innocently.

John was seeing red he was so angry. With lightening speed, John slammed Sherlock against the wall. "I cannot believe you. How ignorant can you be you egotistical prick?" John hissed.

Sherlock said nothing, letting John yell at him instead. "The great Sherlock Holmes can deduce anyone and anything, yet he can't deduce that his best friend is in love with him? He can't deduce that he's an utter arsehole for neglecting to pick up the signs that his best friend so easily put down for him?" John shouted.

"John I-" Sherlock tried to say. "Oh no, I'm not done yet. You are a complete and utter arse, Sherlock Holmes. I made it so obvious for you to deduce my feelings for you, but no. Instead, you decide to choose Molly over me. And to make matters worse, you come up in my room and try to sleep with her. She's not good enough for you. She'll never understand you like I will. And she will never be able to give you everything that I can give you," John spat.

"I can explain," Sherlock tried again.

"You don't get to explain, I don't want to hear it. You want to go after someone like her. Fine. But I don't want anything to do with you then. It's her or me, Sherlock. I can't live with seeing you with her, not when I'm in love with you, and have been since our first case together."

Sherlock doubled back in shock. He had known John's feelings, but he had no idea John had been in love with him for so long. Either way, he finally had what he wanted, and the choice he was offered was the easiest he would ever make in his whole life.

"You," Sherlock simply said.

"I'm sorry, what did you just say?" John asked, pushing Sherlock further into the wall with his forearm.

"I said you, John. I choose you," Sherlock repeated.

"What?" John asked in pure shock. Sherlock burst out laughing.

"Did you really think I was serious about Molly? God no. I've known about your feelings for ages. This was all an experiment. I knew you were never going to tell me, so I gave you the push you needed in order to confess. It had to be you. You had to be the one to come to me, John. If I told you your feelings before you figured them out for yourself, it would have jeopardized our entire relationship," Sherlock explained.

"Hang on, did you just say an experiment? I bloody hate you," John said angrily.

"No you don't, you love me. You're so stupid, John," Sherlock said, shaking his head. John pulled back slightly, looking offended.

"That's not how I meant it. I mean, you're stupid for not realizing sooner that I love you, too," Sherlock said with a smirk.

"I'm sorry, what?" John asked, stunned.

"You heard me, I'm not repeating it again. I care too much about you, John, so of course the feelings are reciprocated," Sherlock said, as if John was dumb for not seeing it sooner.

 "Right... so, where exactly does that leave us?" John questioned.

"Do I really have to spell it out for you? Let's just say we are standing under mistletoe right now and there is nothing I want more than for you to actually do something about it," Sherlock explained.

John glanced up, and sure enough, mistletoe was hanging from his ceiling. It hadn't been there earlier so how was it there now? "Yes, I put it there, John. On purpose, I might add, so that you would get the hint," he said, rolling his eyes and answering the question he knew John was thinking.

'Oh right, the hint. He wants me to kiss him. That really is obvious, how did I miss that?' John thought. Shaking his head, he chuckled and leant up to kiss Sherlock. It was a messy kiss; John relaying his anger and hurt through it, but also his love and adoration.

Sherlock groaned, responding to the kiss eagerly. Neither of them moved apart, both wanting to savor the moment. Finally when his lungs were burning, John pulled away.

"Is that what you wanted?" John panted out.

"Yes... but maybe not quite enough as I had been hoping for," he replied with a smirk.

John attacked his lips again, his tongue sliding past Sherlock's lips and into his mouth. Both men groaned. Months of sexual tension that had been built up was finally released, and it couldn't have been a more pleasing moment.

Neither knew how long they remained up against the wall making out. All that mattered was that Sherlock had been right again, as always. He was never wrong, especially when it came to John.

Sherlock pulled away, breathless. "There's one more thing I have for you," he panted out.

"Hmm?" John hummed.

"The present on the table," Sherlock said, motioning with his head.

John groaned and pulled away from Sherlock to retrieve the box. He pulled off the lid to reveal matching Christmas jumpers and Father Christmas hats.

"Thought maybe we could wear them tomorrow. Besides, you didn't believe you would ever see me wear anything like that, so I just wanted to prove you wrong," Sherlock stated.

"Sentimental bastard," John chuckled affectionately, leaning up to bring their lips together again.

"Merry Christmas, John," Sherlock muttered against his lips.

"Merry Christmas, Sherlock," John replied, before connecting their lips in yet another kiss.

'Oh yes, a merry Christmas indeed,' John thought, as he kissed Sherlock again. It was something he knew he would never grow tired of.

A perfectly imperfect match. A Christmas miracle. The detective and his blogger.


End file.
